Fuel injection pump



-Aug. 7, 1945. R. E. PETERSON I 2,381,555

FUEL INJECTION PUMP Filed Oct. 2, 1941 llllllllillllllllfli m/@2506 I (flay/770174 5. (/6562290/1 Patented Aug. 7, 1945 FUEL INJECTION PUMP Raymond E. Peterson, Riverside, Ill., assignor to International Harvester Company, a corporation of New Jersey Application October 2, 1941, Serial No. 413,269

19 Claims.

The present invention relates to an injection plunger unit for a fuel injection pump particularly designed for internal combustion engines of the compression ignition type. More particularly, the invention relates to that type of pump in which the injection plunger has a controlling face regulating the type and amount'of injec rangement of parts whereby a uniform clamping arrangement may be utilized to prevent distortion of the parts with subsequent excess wear on the reciprocating parts.

Another object is to provide a structural improvement in surge accommodating means both in the intake side of the pump and in the discharge side of the pump.

'The above objects and others which will be apparent from the detailed description to follow are attained by a construction such as shown in the drawing, in which:

Figure 1 is a vertical section through the center of a pump incorporating an injection plunger unit embodying the invention;

Figure 2 is an elevation of the removable unit in its entirety;

Figure 3 is a section taken on Figure 1; and

Figure ,4 is a sectional detail view at right angles to the section of Figure 1, showing the engagement between the control rack and the pump unit.

The injection plunger unit, including the controlling means therefor, as illustrated in the drawing, iriay be utilized for single or multiple cylinder pumps or for pumps having a single pressure supplying unit and a plurality of distributor valves for supplying the universal fuel charges successively to a plurality of engine cylinders. Such a pump is shown in the pendthe line 3-3 of ing application Serial No. 330,750, filed April 20,

1940 t In this application only such arts of the pump casing and the fuel supply and discharge conduits are shown as are necessary to adequately disclose the subject matter of the present invention.-

A pump casing I 0, which is constructed as a casting, is provided with a vertical bore I I extending downwardly from the upper face I2 of the casting. A bore l3, in alinement with the bore ii, is formed at a lower point within the casing ID. A conventional drive shaft ll, mounted in a ball-bearing assembly l5 carries an eccentrically mounted roller 5 for driving the injection piston by means of a tappet cu I! mounted for reciprocation in a bearing sleeve l8 fixed in the bore l3.

The pump unit, which comprises the invention, is formed primarily of a generally cylindrical casing I 9. Said casing is provided at its upper end with a cylindrical bore 20 which joins an intermediate bore 2| of smaller diameter, the offset between the two bores forming an abutment, or shoulder 22. The cylinder of the injection unit is formed with a flanged head portion 23' which slidably fits into the bore 20 abutting the shoulder 22. The cylinder also includes a depending sleeve 24, which is free from contact with any other portion ofthe injection unit. An injection plunger 25 is mounted for reciprocation in the sleeve portion 24 of the cylinder. These parts are fitted by lapping with very close fits for operating atvery high pressures without any substantial leakage. It is essential that this close fit be maintained with a minimum of wear throughout a long period of operation. In

order to provide for long life, it is essential that there be no misalinement or binding of the parts.

It is, therefore, significant that, in the construction of the invention, the flanged portion of the cylinder has a uniform rigid support around its entire periphery and that the sleeve portion of the cylinder is not engaged by other parts of the unit in such a way that clamping pressure might misaline or flex the cylinder walls.

Above the flanged portion 23 of the cylinder, a ported spacer and valve member 26 is slidably fitted in the upper bore 20. A second ported spacer and valve member 21 is slidablyfitted in the bore 20 above the first-mentioned spacer member. A filter element 28, having an annular supporting base 29, is slidably fitted in the bore 20 above the spacer member 21. To secure all of the elements recited rigidly in the barrel or ber 35. Said conduit member 35 is formed with a cylindrical opening 36, which is fitted over the upper cylindrical end portion 31 of the member 30. For supplying fuel to the pump, an inlet conduit may be threaded into the member 35 at the threaded fitting 38. A second conduit fitting 39 is mounted over the cylindrical end 31 of the member 30, said member communicating through a recess 40 with a chamber 4| formed in the upper end' of the member 30. Said chamber communicates through a conduit controlled by a spring-pressed valve 42 with the fuel-supply chamber. The valve seats in a downward direction, being held in seated position by a compression spring. Said valve may be opened by surging in the fuel supply to permit an escape of the fuel, thereby preventing excessive surging in the fuel-supply line connected with the fitting 38. Also, air, collecting inthe upper part of the fuel-supply conduit above the filter chamber 3!, will be bled off through the valve 42. A cap-like fitting 43 is threaded in the charge end of the cylindrical portion of the member 30 for clamping the members 35 and39 in position. Suitable gaskets are provided for maintaining a pressure seal in this low-pressure portion of the pump.

From the filter 28 fuel is delivereddownwardly through conduits 44 and, 45 in the ported spacer members into arcuate recesses 46 formed in the flanged head portion 23 of the cylinder. In order to manufacture the cylinder with these arcuate recesses and orifices 41 extending into the chamber of the cylinder, it is necessary to bore radially through the peripheral wall of the flanged head portion 23. In order to assemble the pump, the cylinder is first dropped into the bore of tire casing and the cap-screws 48 are then screwed into position through openings 49 in the casing. Said screws then also act as looking means to hold the cylinder against rotation.

The piston is provided with a cut-ofi means 50 which regulates the time of injection and the amount of fuel injected. Fuel as delivered by said piston or plunger passes upwardly through a conduit 5| in the lower ported member 26 through a discharge valve 52 into a conduit 53 formed in the upper ported member 21. A compression spring acts to maintain the discharge valve 52 in seated position until fuel is supplied under pressure and to immediately seat the valve when pressure from the piston is relieved by by-passing when the supply cut-off has passed over the by-pass port.

As shown in Figure 3, fuel from the conduit 53 is discharged through a hollow cap-screw 54 and discharged into a conduit member 55. Said member is secured by the cap-screw 54 against a flattened face 56 of the upper ported member 21. In order to provide for attaching the conduit member 55, a portion is milled out of the side of the casing IS. The conduit member 55 is adapted to lead to a distributor valve mechanism or directly to an injection nozzle on an engine cylinder.

To provide for the relief of surging in the fuel discharge line beyond the discharge valve 52 when said valve is seated, a shunt passage is formed by means of a conduit 58 in the ported member 21 and a conduit 59 in the ported member 26. Said conduits communicate with alined bores formed in the ported members. A valve 60 held by a compression spring is fitted against a seat formed around one of said bores. The valve is seated in the direction to remain closed when pressure is greater on the plunger side of the valve 52 and to open for the relief of pressure or surging when pressure is greater on the discharge valve 52. It has been found that this by-pass shunt with the control valve therein is very effective in reducing surging in the discharge line with subsequent irregularities in metering of the fuel.

To prevent misalinement .of the various bores in the ported members 26 and 21, said members are held together against angular movement by key means, such as the pin 6| illustrated in Figure l. The two members are then held against angular movement with respect to the casing by a set-screw 62, as shown in Figure 2.

To provide means for altering the angular position of the injection plunger 25, a control member 63 is mounted in the annular space between the sleeve 24 and the lower portion of the casing and Within the bore 2|. Said member has a bearing portion 64 journaled in the upper end of the bore 2| and a lower bearing portion 64 journaled in a smaller bore 65 provided in a reduced end portion 66 of the casing. A gear 61 is formed on the control member 63 intermediate its ends between the bearing portions. As best shown in Figure 4, a ide wall portion of the casing is cut away to provide an opening 68 through which the gear 61 projects. A control rack 69, mounted for reciprocation in a wall of the pump casing 40, engages the gear 61 and is adapted by longitudinal movement to rotate and angularly adjust the position of the control member. It will be noted that the diameter of the gear 61 is such that the control member 63 may be inserted through the top of the casing l9 and that said gear will project when a side portion of the wall is cut away, as shown in Figure 4, a suificient distance to engage the rack 69, while at the same time the end portion 66 of the plunger unit is sufficiently small to clear the rack 69 for removal of the pump unit. It will be noted that the control member 63 is spaced from the sleeve 24 and is journaled entirely in the casing is at two widely spaced locations. This permits relatively loose and free bearing surfaces without the danger of cocking the member thereby interfering with proper adjustment of the injection piston.

The control member 63 engages the piston 25 by means of a plurality of vertically cut, splinelike grooves 10 which slidably and non-rotatably engage a series of projections "H around the piston below the sleeve 24. This arrangement permits reciprocation of the pump wheel at the same time, providing for angular adjustment by means of the control member.

The lower end of the piston 25 is provided with a head 12 against which a retainer washer i3 is fitted. A compression spring abuts said retainer washer and an annular recess formed around the bottom of the casing l9. In Figure 1, the spring is shown compressed with the eccentric It at its high point of movement. In Figure 2 the spring is shown expanded as the unit is removed from the pump, and no pressure is being applied against the spring.

In order to clamp the member 30 securely in position and to prevent an accidental unscrewing of the member due to vibration, a locking ring M is provided with a series of serrations which are adapted to engage a plurality of mating serrations on the member 30 above the threaded portion thereof. Said locking ring is provided with lugs 15 which are adapted to engage recesses 16 in the upper end wall of the casing I9. Due the large number of serrations, it is relatively easy to thread the member 30 securely into position and subsequently to fasten the locking ring may then be removed without disturbing any other portion of the pump by loosening the capscrews 18 which secure theflange of the casing is to the upper face l2 of the pump casing Hi.

It is to be understood that applicant has shown and described a preferred embodiment of his improvement in unit-type injection pumps and in I control means therefor, and that he claims as his invention all modifications falling within the scope of the appended claims.

What is claimed is:

1. A fuel pump unit for Diesel injection pump comprising a generally cylindrical casing, a uniform bore extending from the top of said casing and a second bore of smaller diameter extending from the termination of said bore to substantially the lower end of the casing, the different diameters ofsaid bores forming a shoulder, a cylindrical control member disposed coaxially of and rotatively within the second bore, a cylinder hav. ing a flange head portion fitted in the largest bore against the shoulder at the bottom end of said bore, said cylinder having a sleeve portion depending downwardly within the control member and spaced from said member, said flanged head portion being providedwith conduits for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending downwardly through the lower end of the cylinder, a radially ported member mounted in the upper bore above the cylinder, means in coaxial threaded relation with the upper end of the bore for clamping said ported member and said cylinder rigidly in position, said casing having a side wall portion cut away to provide an opening adjacent to a port in said ported member, and an outlet conduit extending through said side wall opening andsecured to said ported member communicating with the port therein.

2. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical casing formed with a bore extending downwardly from the top and a second bore of smaller diameter extending from the termination of said bore to substantially the lower end of the casing, the different diameters of said bores forming a shoulder, and a-third bore of smaller diameter than the second bore extending downwardly from the terminating end of the secondbore, a. control member having a lower bearing surface journaled' in .the third bore at the lower end of the casing and a larger cylindrical bearing surface iournaled in a portion of the second bore spaced upwardly from the third bore, said member being provided with a gear formed between the two bearing surfaces "and said casing being cut away at one side to provide for the engagement of a control rack with said g'e'ar, a cylinder having a flanged head portion=fitted inlthe largest bore against the shoulder at'the' bottom end of said bore, said cylinder having a sleeveportion depending downwardly within the control member and spaced therefrom;

said flanged head portion being provided with conduits for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending, downwardly through the lower end of the casing, a ported member mounted in the upper bore against the top of the cylinder, and means threaded into the upper end of the bore for clamping said 'member and said cylinder rigidly in position.

3. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical casing, a uniform bore extending from the top of said casing, a second bore of smaller diameter extending from the termination of said bore to substantially the lower end 01' the casing, the different diameters of said bores resulting in the formation of a shoulder within the casing intermediate its ends, a control member journaled in axially-spaced bearing portions within the casing below said shoulder, said member being provided with a gear formed between two bearing surfaces there of journaled on said axially-spaced bearing portions of the casing, said casin being cut away at one side to provide for the engagement of a. control rack with said gear, a cylinder having a flanged head portion fitted in the casing against the shoulder, said cylinder having a-sleeve portion depending downwardly within the control member in radial spaced relation therewith, said flanged head portion being provided with conduits for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending downwardly through the lower end of the casing, a ported member mounted in the upper bore against the'top of the cylinder, and

means threaded into the upper end of the bore for clamping said member and said cylinder rigidly in position.

4. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical casing, a uniform bore extending from the top of said casing substantially over half the length thereof, a

second bore of smaller diameter extending from inder, a radially ported member mounted above the first member, said upper bore being threaded at its upper end, a clamping member threaded into the top of the casing forming an enclosed fuel intake chamber and holding the ported members and the cylinder rigidly in position in the casing, an upper side wall portion of said casing in the vicinity of the upper ported member being cut away to provide attachment of a fuel discharge conduit with said upper ported member communicatively with a radial port therein and thence further communicating through said radial port and by means 'of an alined vertical bore formed in the first ported member with the pump chamber, and fuel supply means communicating with the closure member for the casing. I

5. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical casing, a uniform bore extending from the top of said casing substantially over half the length thereof, a second bore of smaller diameter extending from the termination of said bore to substantially the lower end of the casing the different diameters of said bores forming a shoulder, a cylinder having a flanged head portion fitting in the largest bore against the shoulder at the bottom end of said bore, said flanged head portion being provided with a conduit for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending downwardly through the lower end of the casing, a cylindrical spacer structure member mounted in the upper bore against the top of the cylinder, said upper bore being threaded at its upper end, a clamping member threaded into the top of the casing forming an enclosed fuel intake chamber and holding the spacer structure member and the cylinder rigidly in position in the casing, the upper portion of said casing in the vicinity of the spacer structure being cut away to provide attachment of a fuel discharge conduit with said spacer structure, said spacer structure being provided with inlet conduit means communicating with the closure member and the conduit in the cylinder flange, and with discharge conduit means communicating with the cylinder and the fuel discharge conduit, and fuel supply means communicating with the closure member for the casing.

6. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical casing, a uniform bore extending from the top of said casing substantially over half the length thereof, a second bore of smaller diameter extending from the termination of said bore to substantially the lower end of the casing, the different diameters of said bores forming a shoulder, a cylinder having a flanged head portion'fltted in the largest bore against the shoulder at the bottom end of said bore, said flanged head portion being provided with conduits for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending downwardly through the lower end of the casing, a cylindrical spacer structure mounted in the upper bore against the top of the cylinder, said upper bore being threaded at its upper end, a clamping member threaded into the top of the casing forming an enclosed fuel intake chamber and holding the spacer structure and the cylinder rigidly in position in the casing, the casing in the vicinity of the spacer structure being cut away to provide attachment of a fuel discharge conduit with said spacer structure, said spacer structure being provided with inlet conduit means communicating with the closure member and the conduit in the cylinder flange, and with discharge conduit means communicating with the cylinder and the fuel discharge conduit, discharge valve means in the discharge conduit means and by-pass surge relief valve means providing a shunt around said discharge valve means, and fuel supply means communicating with the closure member for the casing,

7. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical barrel, a uniform bor'e extending from the top of said barrel, a second bore of smaller diameter extending from the termination of said bore to substantially the lower end of the barrel, the different diameters of said bores forming a shoulder, and a third bore of smaller diameter than the second bore extending downwardly from the terminating end of the second bore, a control member having a lower bearing surface journaled in the third bore at the lower end of the casing and a larger cylindrical bearing surface journaled in the upper end of the second bore, said member being provided with a gear formed between the two bearing surfaces and said casing being cut away at one side to provide for the engagement of a control rack with said gear, a cylinder having a flanged head portion fitted in the largest bore against the shoulder at the bottom end of said bore, said cylinder having a sleeve portion depending downwardly within the control member and spaced from said member, said flanged head portion being provided with conduits for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending downwardly through the lower end of the casing, a ported member mounted in the upper bore against the top of the cylinder, and means threaded into the upper end of the bore for clamping said member and said cylinder rigidly in position.

8. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical casing. a uniform bore extending from the top of said casing substantially over half the length of the casing and a second bore of smaller diameter extending from the termination of said bore to substantially the lower end of the casing, the different diameters of said bores forming a shoulder, 9. control member journaled in the second bore, said member being provided with a gear and said casing being cut awa at one side to provide for the engagement of a control rack with said gear, a cylinder having a flanged head portion fitted in the largest bore against the shoulder at the bottom end of said bore, said cylinder having a sleeve portion depending downwardly within the control member spaced from said member, said flanged head portion being provided with a conduit for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending downwardly through the lower end of the casing, a plunger return spring mounted at the lower end of the casing and against the lower end of the injection plunger, a ported member mounted in the upper bore against the top of the cylinder, at second ported member mounted above the first member,

said upper bore being threaded at its upper end,

a clamping member threaded into the top of the casing forming an enclosed fuel intake chamber and holding the ported members and the cylinder rigidly in position in the casing, the upper portion of said casing in the vicinity of the upper ported member being cutaway to provide an opening, a fuel discharge conduit extending through said opening and attached to said upper ported member, said conduit being in communication with a conduit formed in the upper member and communicating by means of an alined vertical bore formed in the first ported member with the pump chamber, discharge valve means provided in said conduits, a return conduit being provided in said ported members as a shunt around the discharge valve to provide for the return flow of liquid when said valve is closed upon surging of the liquid in the discharge line, said conduit being provided with a valve permitting flow in the direction of the cylinder and sealing the passage against flow in the direction of discharge.

9. A fuel pump unit for Diesel injection pumps comprising a generally cylindrical casing. said casing being formed with a uniform bore extending from the top substantially over half the length thereof, a second bore of smaller diameter extending from the termination of said bore to substantially the lower end of the casing, the different diameters of said bores forming a shoulder, and a third bore of smaller diameter than the second bore extending downwardly from the terminating end of the second bore, a flange surrounding said casing near the central portion thereof provided with means for rigidly securing the unit in position in a pump casing, a control member having a lower bearing surface Journaled in the third bore at the lower end of the casing and a larger cylindrical bearing surface journaled in the upper end of the second bore, said member being provided with a gear formed between the two bearing surfaces and said casing being cut away at one side to provide for the engagement of-a control rack with-sald gear, the outside diameter of the casing below the cut-away portion being smaller than the tooth diameter of said gear to provide clearance whereby the unit may be removed vertically upwardly with the control rack remaining in position, a cylinder having a flanged head portion fitted in the largest bore against the shoulder at the bottom .end of said bore, said cylinder having a sleeve portion depending downwardly within the control member spaced from said member, said flanged head portion being provided with conduits for the delivery of fuel to the cylinder, an injection plunger mounted in said cylinder and extending downwardly through the lower end of the casing, a plunger return spring mounted at the lower end of the casing and against the lower end of the injection plunger, a channeled member mounted in the upper bore against the top of the cylinder, a second channeled member mounted above the first channeled member, said upper bore being threaded at its upper end, a clamping and cover member threaded into the top of the casing forming an enclosed fuel intake chamber and holding the ported members and the cylinder rigidly, in position in the casing, the upper portion of said casing in the vicinity of the upper ported member being cut away to provide attachment of a fuel discharge conduit with said upper ported member, said conduit being in communication with a channel formed in the upper member and communicating by means of'analined vertical channel formed in the first ported member with-the pump chamber, discharge valve provided in said channels, a return conduit being provided in said channeled members as a shunt around the discharge valve to provide for the return flow of liquid when said valve is closed upon surging of the liquid in the discharge line, said return conduit being provided with a valve permitting flow in the direction of the cylinder and preventing flow in the direction of discharge, fuel supply means communicating with the closure member for the casing, an inlet conduit and a relief conduit communicating with said closure member, and a surge valve relief means provided in said relief conduit, said valve being constructed to open upon a momentarily high pressure in the supply line during the end of the intake stroke to provide for the relief of pressure in the supply chamber.

10. In an injection pump; a casing having a side wall indexing means; a pump cylinder having a piston-receiving bore and an end face with which said bore is communicative. an inlet channel leading generall axially into the side wall of such cylinder through said end face at a position spaced from that at which the bore communicates with said face, and lateral channel means extending radially through the cylinder side wall at a position spaced axially inwardly from said face and having an inner portion communicating between the inlet channel and the cylinder bore and an outer portion extending between the inlet channel and the exterior of the cylinder side wall; and plug means within and projecting outwardly from the outer channel portion into coacting relation with the casing indexing means to facilitate the attainment of circumferential alinement of the casing and cylinder.

11. The combination stated in claim 10, but wherein said plug nieans is a screw member in threaded relation with said outer channel portion and said indexing means is an opening in the casing wall through which the screw member is insertable into and withdrawable from said outer channel portion.

12. In an injection pump, a cylinder having a piston-receiving bore and an end face with which I said bore is communicative, and inlet channel means leading generally axially into the side wall of said cylinder through said face at a position spaced from that at which said bore communicates with said face and having a lateral portion that communicates with said bore ata p'osltion thereon disposed axially inwardly from said face; a channeled structure having an end face and disposed in end-to-end relation with said cylinder with said end faces in sealing relation, said structure having an inlet channel means in said structure communicating through said face thereof with the inlet channel means of the cylinder, and an outlet channel means in said structure communicating through said face thereof with the cylinder bore; and means acting through said cylinder and said channeled structure for pressing said faces together in such sealing relation.

13. In an injection pump, a cylinder having a piston-receiving bore communicative with an end face of the cylinder for the discharge of pumped fluid and an inlet channel communicating between said face and a portion of the cylinder bore inwardly from said face independently of said discharge communication of the bore with said face, a channeled member having opposite end faces between which extend an inlet channel and a discharge channel, said channeled member being disposed in end-to-end' relation with the cylinder with one of its faces in sealing relation with the cylinder end face, with said inlet channels and with said discharge".

intercommunicative channel communicative with said discharge communication of the cylinder, said discharge channel having a valve seat in a portion thereof facing toward the other face of said channeled memher, a valve member axially displaceable in said discharge channel for seating upon and unseating from said valve seat, a second channeled member having an end face disposed in opposed sealing relation with said other face of the first channeled member, said second channeled member having a spring-receiving recess in said face thereof in registry with the discharge channel of the first channeled member, a spring in said recess to normally press the valve member on the valve seat, and said second channeled member also having inlet and discharge channels communicating with exterior portions of such member and respectively with the inlet channel of the first channeled member and said spring-receiving cess.

14. In an injection pump, a pump cylinder having an end face with separate inlet and discharge openl ii a casing projecting endwise from said cylinder, a pair of into said casing onto one of said members adjacent to the cylinder having an end face in sealed relation with the cylinder end face and the faces of said stacked members opposed to one another also being in sealed relation, the member adjacent to the cylinder having a discharge channel extending between its faces communicatively with the cylinder discharge opening, said members having inlet channels alined with one another and with the cylinder inlet opening to provide communicationfrom the latter axially through said stacked members, a valve seat within the discharge channel of the one member, a valve member cooperable with said seat and movable toward the cylinder to rest on said seat and away from the cylinder to raise from said seat, a spring-receiving recess in the other channeled member communicating with the discharge channel of the one member beyond the valve seat, a spring in said recess for urging the valve member into its seated position, said other channeled member also having a discharge channel leading radially from the spring-receiving recess to a side of such member, and means cooperative with said casing for pressing said cylinder and said channeled members axially together.

15. In an injection pump, a pair of channeled members having opposed faces fitted together in sealed relation, a discharge channel having serially arranged counterparts respectively in said membersand intercommunicative at said faces, one-way-flow valve means in said channel to permit the flow of fluid therethrough only from the channel'counterpart in one of said members to the channel counterpart in the other member upon the creation of a fluid pressure of predetermined magnitude tending to cause such flow, and by-pass means in shunting relation with said oneway-flow valve means comprising a by-pass channel having counterparts respectively in said channeled members where they communicate with the discharge channel counterparts and extend to said opposed member faces where they intercommunicate, and one-way-ilow valve means in said by-pass channel to permit a reverse flow of fluid therethrough from the channel counterparts in said other members to the channel counterparts in the one member upon the creation of a redetermined fluid pressure tending to cause such reverse flow.

16. In an injection pump, a pair of channeled members having opposed faces fitted together in sealed relation, said members being traversed by a discharge channel having serially connected counterparts respectively in said members and leading to said faces where they register for intercommunication, a valve seat in the channel counterpart of one member facing toward the other member, a valve member seatable on said seat to close said channel but displaceable from said seat toward said other member to open the channel, a spring in the chann l counterpart of the other member'and acting upon said valve member to impositively hold the same seated, and by-pass means in shunting relation with said valve seat channeled members stackedthe cylinder end face, the

and valve member comprising a by-pass channel having counterparts respectively in said channeled members in communication with the discharge channels therein and extending to said faces into inter-communication, a by-pass valve seat in the by-pass channel counterpart in said other member facing toward the one member, a by-pass valve member seatable on said by-pass valve seat to close the by-pass channel but displaceable from such seat toward the one member .to open such by-pass channel, and a spring in the by-pass channel counterpart of the one member and acting upon the by-pass valve member to impositively hold the same seated.

1'7. In an injection pump; a channeled member having a surface portion of predetermined profile and a fluid conducting channel communicating with the surface of said member through said surface portion; a conduit having upon a side wall thereof a surface portion profiled to fit in sealed relation over an extensive area of the surface portion of said channeled member, said conduit having a hole axially alined with said channel while said surface portions are in such sealed relation and a channel leading laterally from said hole; and a fastening member having a portion extending through said hole into said channel for pressing said surface portions firmly into said sealing relation, and said fastening member having an axial channel with ports respectively communicating with the channels of said memberand of said conduit.

18. In an injection pump; a channeled member having a surface portion of predetermined profile and a threaded fluid conducting channel communicating with the surface of said member through said surface portion; a conduit havin upon a side wall thereof a surface portion profiled to fit in sealed relation over an extensive area of the surface portion of said channeled member, said conduit having a hole axially alined with said channel while said surface portions are in such sealed relation and a channel leadin laterally from said hole; and a headed fastening member having 'a threaded shank insertable through said hole into meshed relation with the threads in the channel of said member for plugging said hole and for pressing said surface portions firmly into said sealing relation, and said fastening member shank having an axial channel with ports respectively communicating with the channels of said member and of said conduit.

19. In an injection pump, a pump cylinder having an end face with separate inlet and discharge openings, a casing projecting endwise from said cylinder, a pair of channeled members stacked one beneath the other in end to end relation into said casing onto the cylinder end face, the one of said members adjacent to the cylinder having an end face in sealed relation with the cylinder end face and the faces of said stacked members opposed to one another also being in sealed relation, the member adjacent to the cylinder having a discharge channel extending between its faces communicatively with the cylinder discharge opening, said members having inlet channels alined with one another and with the cylinder inlet opening to provide communication from the latter axially through said stacked members, a valve seat within the discharge channel of the one member, a valve member cooperable with said seat and movable toward the cylinder to rest on said seat and away from the cylinder to raise from said seat, a spring-receiving recess in the stacked in said casing onto the other channeled member to strain the fluid prior to its entry into the inlet channels, and means cooperative with said casing for pressing said cylinder and said channeled members axially together.

RAYMQND E. PETERSONQ 

